The proposed project represents an investigation of the developmental changes in pattern perception in the first year of life. The specific goals are: 1) to test the hypothesis that visual attention in very young human infants is determined largely by the intensity of stimulation and that only after a few months of visual experience do infants become capable of responding to the qualitative aspects of visual stimulation, such as form; and 2) to investigate the relative effectiveness of several dimensions of visual stimulation. The project involves three studies. The first two are designed to test one- to six- month-old infants with the visual preference method. By measuring in a developmental, cross-sectional design how long the infants fixate the stimuli, which will be designed to pit intensity of stimulation against pattern or form, it will be possible to examine the relative influence of the quantitative and qualitative aspects of visual stimulation as well as to discover whether and when a change in the bases for attention occurs. A third study has been designed to investigate the stimulus bases of pattern discrimination in eight- to twelve-month-old infants. Using a transfer of training technique, it will be possible to vary the transfer stimuli to see what stimulus aspects were most important in determining the learned discrimination. The three studies should provide empirical developmental data, important for theory and practice.